The wife of an IRA informer has launched a High Court bid for permission to sue a man alleged to have been the highest-ranking British agent within the Provisionals.

Lawyers for Margaret Keeley want to be allowed to name west Belfast man Freddie Scappaticci as a co-defendant in her damages claim against the Chief Constable.

Scappaticci (64) denies allegations that he was the military spy codenamed Stakeknife.

Mrs Keeley, whose husband is the one-time MI5 agent known as Kevin Fulton, has issued proceedings against the police for alleged wrongful arrest and false imprisonment.

The case has been brought over her alleged detention at the Castlereagh holding centre in 1994 after an IRA attempt to murder senior RUC detective Derek Martindale in east Belfast.

She claims that after being released she was taken to a house in the New Lodge, north Belfast and interrogated by a number of IRA men. Mrs Keeley says she later suffered a nervous breakdown as a result of her ordeal.

Scappaticci was thrust into the spotlight in 2003 when British and Irish media claimed he was the double agent Stakeknife, an allegation he categorically denied. He has since secured a court order banning any publication of his current whereabouts.

As part of Mrs Keeley's case she is now attempting to widen her claim to include both Scappaticci and the Ministry of Defence.

After a brief hearing in the Masters Court, Mrs Keeley's solicitor, Kevin Winters, confirmed: “The application today was to seek the court's permission to join Mr Scappaticci and the MoD as co-defendants in the action.

“It was adjourned for four weeks to allow his lawyers to prepare and file a replying affidavit.”

If the application is granted writs will then be served on both Scappaticci and the MoD.